I only know how to modify Jahan and Madora. I will give you a little bit of help how, it should be enough for you to eventually figure it out.

1)Open Character.xlsm
2) Find Henchman_Jahan_Mage and/or Henchman_Madoc_Paladin
3) Talents are under the column "Talents" (column BV)
4) Link by Pestilence so you can know talen ids. https://docs.google.com/spreadsheets/d/1LSXwKfmqlDCAZLlJCFyrvKslZmVK8BHlxK5K0nh0Wa4/pubhtml

Ex: want to add Packmule to Lydia Madora? then change
AttackOfOpportunity;WhatARush;ResistDead
to
AttackOfOpportunity;WhatARush;ResistDead;Carry

To change their starting level edit column "Act part" (Column D). PS If you make them level 1 they will auto level up to the level of the player that recruited them (which is great).

5) Then open up All.xlsm (its in the same location as the Character.xslm. Then press Generate. wait a while and it will add the changes to Character.txt.

6) Now you can move the Character.txt to your public/yourmodfolder. I guess you already know this, if not you should be able to figure it out.

7) To edit their starting skills you need to edit SkillSet.xlsm just find their names and you should figure it out. Becareful not to leave any empty grids on column B so make sure to cut and paste everything under madora/jahan to accommodate the removed/added skills.

**** Here are some good links for information. ****
Editor Guides & Resources (lstools on 2nd comment)
http://www.larian.com/forums/ubbthreads.php?ubb=showflat&Number=505777

Custom Henchman Tutorial & Guide
http://www.larian.com/forums/ubbthreads.php?ubb=showflat&Number=508931#Post508931

[Tutorial] Main Campaign Mods
http://www.larian.com/forums/ubbthreads.php?ubb=showflat&Number=514372#Post514372

Modding Guide if you want to mod the main campaign
http://www.larian.com/forums/ubbthreads.php?ubb=showflat&Number=504576